Rotor assembly for food waste disposers



INVENTOR. 660/92 0. .fifie/wm/g/c ATTOENE 5.

X 2 7 wk mm a G. O. SHERMAN, JR

Filed Oct. 16. 1961 Oct. 12, 1965 ROTOR ASSEMBLY FOR FOOD WASTE DISPOSERS United States Patent 3,211,389 ROTOR ASSEMBLY FOR FOOD WASTE DISR'OSERS George 0. Sherman, Jr., Prairie Village, KiE1S., assignor to The Salvajor Company, Kansas City, Mo., a corporation of Missouri Filed Oct. 16, 1961, Ser. No. 145,041 5 Claims. (Cl. 241-257) This invention relates to waste disposers, and more particularly to apparatus for reducing food waste material to small particles for discharge to a sewer.

It is well known to provide food disposers with grinding lugs secured to a rotor and disposed to cooperate with a stationary grinding surface in the disposer for grinding and shredding waste materials and garbage. The best and most efiicient comminution of the materials is accomplished when the grinding lugs are rigidly and unyieldably secured to the rotor. Thus, it has been conventional to rigidly secure the lugs to the rotor and prevent any relative movement therebetween. Although disposers equipped with these stationary lugs achieve the best grinding action, they readily become jammed when a substantially uncomminutable material, such as silverware, glass or the like, becomes lodged between the lug and the grinding surface. Each time such jamming occurs, the machine must be shut down until the hard material is dislodged.

To avoid such shut down, particularly in restaurants or the like, requiring large amounts of waste disposal service, the use of swingable lugs that yield when contacted by such solid materials, has been attempted. The freely yielding lugs or hammers sacrifice some of the grinding efiiciency of the fixed lugs. However, since shut-downs are virtually eliminated, such lugs have met with success. A need exists however, for a lug for disposers which achieves the advantages of both the fixed and swingable types without the disadvantages of either.

Accordingly, it is the most important object of this invention to provide a rotor for a waste food grinder having structure for holding the grinding lug rigidly in grinding position during normal waste-grinding operations, thereby obtaining the most effective comminution of the waste material.

In conjunction with the foregoing object, it is an equally important object of the instant invention to provide a rotor having such a normally rigidly sustained grinding lug, yet capable of automatic displacement of the lug to permit unjamming when abnormally hard objects are encountered by the waste grinder.

It is a particularly important object of the invention to provide a rotor assembly for food waste dispensers wherein the rotor has at least one freely swingable grinding lug thereon and normally biased toward the outer grinding surface of the disposer housing during rotation of the rotor and with pin means being interposed in the path of swinging of the lug to maintain the latter in predetermined relationship with respect to the grinding surface of the housing, the axis of rotation of the rotor and the axis of swinging of the lug so that the lug is normally rigidly maintained in grinding position but will give way sufficiently by swinging away from the housing to clear an obstruction before such obstruction will lodge between the outer grinding face of the lug and the housing to stop rotation of the rotor.

Another important object of this invention is the provision of a waste food grinder rotor having grinding lugs which automatically swing completely clear of the grinding surface upon counterrotation of the rotor to thereby permit quick and easy dislodgment of any solid objects by simply reversing the motor and without the necessity 3,Zll,389 Patented Oct. 12, 1965 of having a high starting torque motor or shutting down the waste disposal operation for an extended time.

A yet further object of this invention is the provision of a rotor having one or more lugs which will automatically return to their normal, rigidly sustained, grinding position after the uncomminutable material has been released, thereby obviating any necessity for halting the grinding operation to reset the dislodged lugs.

Still another very important object of this invention, and cooperating in the achievement of the foregoing object, is the provision of structure carried by each swingable grinding ing to prevent waste food partitcles from entering between the lug and the pin which holds the lug in its normal grinding position, thereby precluding the clogging of such particles in the path of swing of the lug to prevent the latter from automatically resuming such position.

In the drawing:

FIGURE 1 is a plan view of the rotor of a food waste disposer constructed pursuant to the principles of this invention, with a part of a grinding lug being broken away and shown in cross section for clearness;

FIG. 2 is a fragmentary, cross-sectional view taken along line 22 of FIG. 1; and

FIG. 3 is a fragmentary, cross-sectional view taken along line 3-3 of FIG. 2.

Briefly, this invention relates to a rotor for a food waste disposer having grinding lugs mounted thereon which are normally held in a fixed grinding position, but which are pivotally coupled thereon for swinging away from such position when acted upon by a force which would ordinarily result in jamming of the machine.

The point of pivot of the lug and the axis of rotation of the rotor, are situated relative to the grinding edge of the lug (along which any jamming forces would necessarily act) to permit swinging of the lug from its grinding position to automatically relieve any jamming forces which might occur. A flange on the lug protects against waste material entering between the lug and its retaining pin, and preventing the lug from entering its grinding position. Additionally, the L-shape of the lug permits the latter to be swung from its grinding position when the direction of rotation of the rotor is reversed, thereby freeing any relatively solid material which may become lodged between the grinding edge of the lug and the fixed grinding surface of the disposer.

A food waste disposer 10, shown fragmentarily in FIG. 2, includes a hopper 12 adapted to be secured to the outlet opening of a sink (not shown), a shredding ring 14, a discharge chamber 16, and a rotor 18 secured to the shaft 20 of a motor (not shown). Shredder ring 14 is disposed beneath hopper 12 and has a frusto-conical side wall 22 having a plurality of projections 24 extending from the inner surface of wall 22 and disposed to break up larger particles of food waste material which may be impelled against projections 24. A grinding surface 26, adjacent the lower margin of wall 22, is provided at its lower margin with a plurality of slots 28 for permitting the finely ground particles of food waste material to pass from within shredder ring 14 and into discharge chamber 16 where they may be discharged to a drain pipe connnected to a sewer or the like, through outlet 30.

Rotor 18 has a generally flat, circular, upper surface 32 extending to the inner edge of the lowermost margin of wall 22 and may be provided on surface 32 with a pair of stationary lugs 34 for impelling food waste material outwardly toward the grinding surface 26.

Grinder means in the form of generally L-shaped lugs 36 are pivotally coupled to upper surface 32 by hinge pins 38 which are spaced radially inwardly from the outer peripheral margin of rotor 18. The point of pivot of lugs 36 to rotor 18, is adjacent one end of a forwardly extending leg 40, and each lug 36 has an outwardly extending leg 42 integral with leg 40. The outer edge 44 of leg 40 is complementally disposed in relatively close, spaced relationship from grinding surface 26 to cooperate with the latter in the grinding of food waste materials into comminuted particles for passage through slots 28 and into discharge chamber 16.

The center of mass of the lugs 36 is spaced from the point of pivot at pins 38 to permit swinging of the lugs 36 outwardly to their normal grinding positions. Rotor 18 is normally rotated in a counterclockwise direction, as viewed in FIG. 1. The extent of outward swinging of the lugs 36 in a clockwise direction about hinge pins 38 as rotor 18 rotates in a counterclockwise direction about its axis of rotation on shaft 20, is determined by limiting means including a stop 46 rigidly secured to rotor 18 and projecting upwardly from surface 32 in position to be engaged by lug 36.

A flange 48 extends outwardly from leg 40 and rearwardly from leg 42 in overlying relationship with stop 46, to provide means for preventing objects such as food waste material or the like, from getting between the lug 36 and its respective stop 46 to prevent the lug 36 from swinging to its normal grinding position. The outer edge of flange 48 is integral with and is an extension of grinding edge 44, and likewise cooperates with grinding surface 25 to effect pulverizing of food waste material. Each lug 36 has a leading edge or surface comprising a portion 52 extending inwardly from grinding edge 44 generally parallel with leg 42 and a portion 54 extending diagonally from portion 52 to the inner edge of leg 40. Both portions 52 and 54 of the leading edge of lug 36, are beveled to slope rearwardly in the direction of hinge pin 38 to facilitate the sliding of food waste material over lug 36.

A second stop 56 for each lug 36 is disposed to be engaged by portion 52 of the leading edge after lug 36 has been swung in a counterclockwise direction about its hinge pin 38 a predetermined amount. The amount of permitted swing is somewhat less than 180 from the normal grinding position, but is sufficiently far to permit grinding edge 44 to be withdrawn from grinding surface 26 for permitting the unjamming of the disposer.

In operation, rotor 18, rigidly secured to shaft 20, rotates with the latter in a counterclockwise direction under the motivation of the disposer motor. The counterclockwise rotation of rotor 18 causes the lugs 36 to swing outwardly to their normal grinding positions through the bias of centrifugal force. The centrifugal force, assisted by the force of food waste material on surface 32, acting against portions 52 and 54 of the leading edge of lug 36, holds the latter in position. The larger particles of food waste material are broken up by projections 24 and fall onto the surface 32 where they may be engaged by lugs 34 for further breaking and Where they are projected outwardly against wall 22 of the shredder ring by centrifugal force. The particles gravitate to grinding surface 26 adjacent the lower margin of wall 22 where they are engaged by the grinding edge 44 of lug 36 which cooperates with grinding surface 26 to pulverize and grind the material to be forced through slots 28 into the discharge chamber 16 for disposal to a sewer system. The stop 46 for each lug 36 is normally engaged by the latter throughout the grinding operation and serves to hold the lug into fixed position, resisting any tendency of the lug to be swung away from grinding surface 26 by the normal grinding action of ordinary food waste materials. Thus, during normal operation, lug 36 cooperates with stop 46 to function as a fixed position lug to achieve maximum grinding effectiveness.

However, if, in the course of grinding food waste material, objects are encountered which would ordinarily overcome the rotating force of the motor of disposer and result in the jamming of the latter, the novel design of lug 36 operates to automatically unjam the disposer. Any such material would have to be encountered by grinding edge 44 in order to effect jamming. If such material were encountered by the forward corner or edge of lug 36 adjacent grinding surface 26 and denoted A in FIG. 1, that material would be acted upon by lug 36 with a force, the direction of which coincides with, i.e. acting along a line passing through hinge pin 38 of lug 36 and point A.

The material would also be acted upon by a force exerted by lug 36 and comprised of the centrifugal force imparted to the latter by the rotation of rotor 18. The direction of such force lies or acts along a line extending through the axis of rotation of rotor 18 and point A. The resultant of these two forces is a force directed midway or acting along a line passing between the direction of the two component forces, i.e. between axes of rotation of rotor 18 and pin 38. If the jamming material is sufiiciently solid to resist being pulverized by the grinding means, it will be sufficiently strong to exert an oppositely directed force against lug 36 to overcome the force exerted on the material by lug 36. As long as the oppositely directed force does not pass through the point of pivot of lug 36 with respect to rotor 18, the lug 36 will be caused, by this opposite force, to rotate in a counterclockwise direction about hinge pin 38 to thereby yield to the force imparted upon lug 36 by the material at point A.

Inasmuch as hinge pin 38 is disposed adjacent the rearmost end of the rearwardly extending leg 40, and the center of mass of lug 36 is disposed in spaced relationship forwardly from hinge pin 38, the resultant of the forces acting upon lug 36 to overcome the forces tending to hold the latter in its normal grinding position, will never pass through the point of pivot of hinge pin 38; in fact, it is preferred that it not pass through any part of hinge pin 38, but of course such depends on the diameter of the pin chosen for mounting the lugs. If these factors are substantially adhered to, the lug 36 will be permitted to yield, thereby effecting the automatic unjamming of the disposer. To illustrate this fact, even if the material tends to jam at the rearmost grinding edge located at the rear corner of flange 48 adjacent surface 26, and indicated point B in FIG. 1, the forces acting upon the material lie along lines passing through hinge pin 38 and point B, and shaft 20 and point B. The resultant of these forces also lies forwardly of hinge pin 38 and also permits swinging of lug 36 in a counterclockwise direction to effect automatic unjamming of the disposer.

Manifestly, since it has been demonstrated that such materials acting upon the two extreme ends of grinding edge 44 will permit such unjamming, such unyielding material at any point between points A and B on grinding edge 44 will also automatically result in the unjamming of the disposer. Thus, it is apparent that what has been provided is a rotor provided with a lug which is normally held in a fixed grinding position during contact with normal food waste material to effect maximum grinding of the latter, whereas the novel arrangement of the grinding lug 36 with respect to its point of pivot at hinge pin 38 and grinding edge 44, permits the yielding to automatically unjam the disposer when unusually solid material is encountered.

Additionally, the inward spacing of binge pin 38 from the outer peripheral margin of rotor 18, provides for the outwardly extending leg 42 of lug 36 and permits the reversal of the direction of rotation of rotor 18 to effect counterclockwise swinging of lugs 36. Should a relatively solid object become wedged between grinding edge 44 and grinding surface 26, and in some manner preclude automatic unjamming of the disposer, the motor may be energized to rotate in the opposite direction from the normal counterclockwise direction. The waste material lying upon surface 32 could then contact the normally trailing edge of the outwardly extending flange 48 and the outwardly extending leg 42, to act upon lug 36 and swing grinding edge 44 away from grinding surface 26. It may be readily seen that such swinging of lug 36 would be limited by stop 56. This, of course,

permits sufficient clearance between edge 44 and surface 26 to free any object which would be lodged therebetween. The disposition of the respective stops 56 on surface 32 however, do not permit a full 180 of swing of the lug 36 and maintain the center of mass of the latter spaced forwardly from the point of pivot of hinge pin 38. This insures that when the motor is again energized to eifect rotation of rotor 18 in a counterclockwise direction, lugs 36 will be swung outwardly by centrifugal force to their normal grinding positions.

It should be specifically pointed out that the construction set forth above eliminates the need for a high starting torque motor to bring about release of the jamming material by reversing the direction of the rotor. On the contrary, the force of the jamming material against the lug, when rotor 18 is reversed, readily swings lug 36 about its point of pivot to cause immediate release of the material. Thus, the torque required to reverse the jammed rotor is not appreciably greater than that required for normal rotation of the rotor.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In a waste disposal unit:

a rotor;

21 shredder ring surrounding said rotor;

an L-shaped lug having a pair of legs;

means coupled with one of the legs adjacent one end of the latter and pivotally mounting the lug on the rotor for swinging movement toward and away from the periphery of the rotor and into and out of a waste-grinding position adjacent said periphery, the lug being movable toward said periphery by centrifugal force as the rotor rotates, said one leg of the lug extending circumferentially of the rotor and in advance of said mounting means, the other leg extending substantially radially of the rotor toward said periphery; and

stop means preventing said lug from moving beyond said position by said centrifugal force.

2. The invention of claim 1, said other leg having a leading surface, a trailing surface and a peripheral surface, the latter spanning the distance between the leading and trailing surfaces and extending circumferentially of the rotor concentric to the axis of rotation of the latter.

3. In a waste disposal unit:

a rotor;

a shredder ring surrounding the rotor;

means pivotally mounting the lug on the rotor for swinging movement toward and away from the periphery of the rotor and disposed to maintain the lug adjacent said periphery by centrifugal force, whereby said lug, in conjunction with said ring, grinds waste as said rotor rotates, said 1ug extending from said mounting means in the direction of rotation of said rotor; and

stop means on said rotor and disposed inwardly of said periphery in underlying relationship to the lug for limiting the extent of movement of the lug toward said periphery under the influence of said force.

4. In a waste disposal unit:

a rotor;

a shredder ring surrounding the rotor;

an L-shaped lug presenting a pair of legs;

means coupled with one of the legs adjacent one end of the latter for pivotally mounting the lug on the rotor for swinging movement toward and away from the periphery of the rotor and disposed to maintain the lug adjacent said periphery by centrifugal force with the other leg extending substantially radially of the rotor toward said periphery, whereby said lug, in conjunction with said ring, grinds waste as said rotor rotates, said lug extending from said mounting means in the direction of rotation of said rotor; and

a stop beneath said other leg and engageable thereby for limiting the extent of swinging movement of the lug toward said periphery.

5. In a Waste disposal unit:

a rotor;

a shredder ring surrounding the rotor;

an L-shaped 1ug presenting a pair of legs;

means coupled with one of the legs adjacent one end of the latter for pivotally mounting the lug on the rotor for swinging movement toward and away from the periphery of the rotor and disposed to maintain the lug adjacent said periphery by centrifugal force with the other leg extending substantially radially of the rotor toward said periphery, whereby said lug, in conjunction with said ring, grinds waste as said rotor rotates, said 1ug extending from said mounting means in the direction of rotation of said rotor, said other leg having a leading surface, a trailing surface and a waste-engaging surface, the latter spanning the distance between the leading and trailing surfaces and extending circumferentially of the rotor con centric to the axis of rotation of the latter; and

a stop on the rotor disposed for engagement by said trailing surface for limiting the extent of swinging movement of the lug toward said periphery.

References Cited by the Examiner UNITED STATES PATENTS 1,761,083 6/30 Liggett 241-32 2,442,812 6/48 Jordan. 2,577,152 12/51 Powers. 2,629,558 2/53 Miller 241194 X 2,767,927 10/56 Green. 2,819,847 1/58 I-Iauser. 2,939,639 6/60 Coss. 2,980,348 4/61 Jordan.

I. SPENCER OVERHOLSER, Primary Examiner.

ROBERT A. OLEARY, Examiner. 

1. IN A WASTE DISPOSAL UNIT: A ROTOR; A SHREDDER RING SURROUNDING SAID ROTOR; AN L-SHAPED LUG HAVING A PAIR OF LEGS; MEANS COUPLED WITH ONE OF THE LEGS ADJACENT ONE END OF THE LATTER AND PIVOTALLY MOUNTING THE LUG ON THE ROTOR FOR SWINGING MOVEMENT TOWARD AND AWAY FROM THE PERIPHERY OF THE ROTOR AND INTO ANDOUT OF A WASTE-GRINDING POSITION ADJACENT SAID PERIPHERY, THE LUG BEING MOVABLE TOWARD SAID PERIPHERY BY CENTRIFUGAL FORCE AS THE ROTOR ROTATES, SAID ONE LEG OF THE LUG EXTENDING CIRCUMFERENTIALLY OF THE ROTOR AND IN ADVANCE OF SAID MOUNTING MEANS, THE OTHER LEG EXTENDING SUBSTANTIALLY RADIALLY OF THE ROTOR TOWARD SAID PERIPHERY; AND STOP MEANS PREVENTING SAID LUG FROM MOVING BEYOND SAID POSITION BY SAID CENTRIFUGAL FORCE. 